I would recommend reading the series in publication order. When I started reading the books, I decided to go with chronological order. I picked up Lord Brocktree but was already confused by the intro, so I skipped to Martin the Warrior and continued from there. While it did make sense, I honestly would rather have read them in publication order. I feel like it would make some things more of a surprise and would just have worked better.
If you ever need to check if a name is already used, go look it up on the Redwall Wiki :3 that's what I always do. Just type the name into the search box and if nothing comes up, then you've got an original name.
O_O Well once again I totally missed out on this because I was away from these forums for a while... ^^; So even though this is really really late I want to say THANK YOU!!!!!!!!!! to everyone who posted!! It's really nice of you all to remember about me even when I'm not here I'll try to be around for next time!! ^^;